1. Field of the Invention
This invention relates to disc brakes, and more particularly to sliding caliper disc brakes for automobile vehicles.
2. Discussion of the Background
Conventional sliding caliper disc brakes include inner and outer friction pads which are slidably mounted on a fixed torque-taking member and are positioned at both sides of a rotatable disc, respectively, and a caliper which is slidably mounted on the torque member so as to straddle the minor portion of the periphery of the rotatable disc. The caliper has a forked arm which is brought into contact with a rear surface of a back plate of the outer friction pad to thereby urge the outer friction pad onto one side of the disc. The caliper also has a cylinder within which a fluid actuated piston is positioned so as to be brought into contact with a rear surface of a back plate of the inner friction pad to thereby urge the inner friction pad onto the other side of the disc. The connection between the caliper and the torque member is completed at the side of the inner friction pad by a single pin to permit sliding of the caliper in a direction parallel to the axis of disc rotation and also pivoting of the caliper about the pin. This pivoting of the caliper on the torque member in an outward direction about the axis of the pin is restrained by the contact between an extension formed in the caliper and an extension formed in the torque member while pivoting of the caliper in an inward direction about the axis of the pin is restrained by the contact between a bridge portion of the caliper and the back plate of the inner friction pad by means of the leaf spring means. The pin is connected to the caliper by means of a screw and is slidably inserted within an opening in the torque member. A resilient sealing boot protects the sliding surface of the pin from the ingress of dirt and moisture.
In such prior sliding caliper disc brakes, when the exchange of the friction pads is desired, the screw has to be released for removal of the caliper from the torque member. In assembling the caliper, furthermore, the screw should in assembly be turned with a high degree of accuracy between the caliper and the pin to thereby secure the smooth sliding of the caliper. Therefore, less maintenance and repairs are required. In addition, since the caliper is supported with respect to the torque member at only the side of the inner friction pad, the rigidity required to support the caliper with respect to the torque member will be small. The pivoting force of the caliper in the inward direction is received by the portion of the torque member to support the pad by means of the leaf spring means and the back plate of the inner friction pad and therefore the sliding resistances will occur between the caliper and the leaf spring means and between the leaf spring means and the back plate of the inner pad upon operation of the brakes. Thus, the braking force may be reduced.